Species: 70-170 μm long, 25-36 μm wide; cell body cylindrical; anterior rounded and posterior tapered; spiral striation; nucleus posterior; flagellum longer than body; stigma about 7 μm in diam., many fusiform chloroplasts aligned with the striae; numerous haematochrome granules; paramylum bodies ovoid (Kudo, 1966).

31 μm 63 μm 94 μm; x 640

Images of collecting locality: Ko-sumida river near Sakae-bashi (Sakae bridge), Kasukabe city, Saitama Pref., Japan, February 12, 2006 by Y. Tsukii